Grate



July 20; 1937. l. 0. SMITH 2,087,361

GRATE Filed Aug. 11, 1936 Patented July 20, 1937 UNITED I STATES 2&87361 PATENT orrlcs 2 Claims.

This invention relates to furnace grates in general, and particularly to that type in which the grate bars are mounted to rotate in a supporting frame.

The main object of the invention is to provide a grate composed of sections fixed to shafts adapted to be revolved and constructed so as to support the fuel normally; and, when revolved, to cut out all ashes and clinkers from the fire and present new fire supporting surfaces during the revolution of said shafts to prevent the fuel itself from falling into the ash-pit.

Other objects of the invention will become apparent as the detailed description thereof proceeds.

In the drawing:

Fig. 1 is a fragmentary vertical section through a gravity feed furnace provided with my improved grate;

Fig. 2 is a section taken on the line 22 of Fig. 1;

Fig. 3 is a fragmentary side elevation of mechanism for revolving the bars of the grate;

Fig. 4 is a section taken on the line 44 of Fig.

2, the grate being shown in side elevation;

Figs. 5, 6, '7 and 8 are explanatory diagrams, illustrating the different positions assumed by the grate bars during a complete revolution thereof.

As shown in the drawing the invention comprises a substantially rectangular frame having sides i and 2 connected by ends 3 and 4. The width of the frame will depend upon the width of the firebox of the furnace intended to receive the grate. The sides 3 and 4 are provided with slots 5 to form bearings for the shafts 6 which carry the fire supporting members I. Latch plates 8 provided with slots 9 are pivoted to the sides 3 and 4 to lock the shafts 6 in their slots 5, as shown in Fig. 4.

The sides 3 and i are suitably secured to the walls In and II of the furnace fire box I2, the wall 10 being provided with apertures i3 through which the shafts 6 project. The shafts 6 have their ends squared to receive the worm gears H1- which mesh with and are rotated by a worm l5 journaled in bearing brackets l6 and I? fixed to the wall H3.

The end of worm l5 adjacent bearing bracket i6 has a bevel gear I8 fixed thereto and meshing with a bevel gear i9 which is fixed to a stub shaft 293 journaled in a bearing 2|. The bearing 2i is formed on the end of an arm 22 projecting from bearing l6; and a handwheel 23 fixed to the stub shaft 20 is used to rotate said stub shaft and connected gearing. As shown in the draw- (Cl. INF-35) ing, the shafts 6 are all connected for rotation in the same direction by the worm gear mechanism just described.

Each of the members 1 comprises a fire supporting part 24 having an arcuate surface 25 struck from the axis of shaft 6 as center. The surface 25 in cross section is somewhat less than a semi-circle and is shaped symmetrically with respect to a plane passing through the axis of shaft 6. When the grate is in normal fire supporting position, the ends of adjacent surfaces 25 are quite close to each other as shown in Fig. 5. It will be understood, of course, that the members 7 are properly spaced along their shafts 6 to provide for proper draft through the fire box.

Each member I includes a finger 26 extending from the axis of shaft 6 in a direction opposite to the surface 25; and the end of this finger is curved slightly to form a sort of cutter or scoop 21. The finger 21 is designed so as to sweep quite close to the surface 25 when the shafts 6 rotate through the positions shown in Figs. 6 and 8 during a dumping operation.

The normal fire-supporting position of the grate bars is shown in Figs. 1, 2, and 5 of the drawing. To start a dumping operation, the bars are rotated in the direction indicated by the arrows in Figs. 1, 5, 6, 'l, and 8. As the bars rotate, the fingers 26 rise toward the arcuate surfaces 25 of the members 24, until, after a A; rotation, they assume the position shown in. Fig. 6. A continuation of this rotation causes the curved ends 21 of the finger 26 to cut into the layer of ashes and clinkers and to remove a part of this layer. Where the fingers 26 are in the position shown in Fig. 7 the adjacent ends of the members 24 are substantially in contact and operate as a support to prevent dumping of the loosened layer of ashes and clinkers. Rotation to the position shown in Fig. 8 dumps most of the loosened ashes into the ash pit. From this position the upper end of the members 24 also operate as scoops to remove a final layer of ashes and clinkers from the fire bed.

What I claim is:

1. A cutting and dumping grate comprising a substantially rectangular frame, shafts rotatable about parallel axes journaled in opposite sides of said frame, fire supporting members spaced apart along each of said shafts, the adjacent ends of the segments on adjacent shafts being substantially in contact with each other when the members are in normal fire supporting position, each member having a finger projecting in the general direction of a plane bisecting the segends to form scoops for cutting into the superposed layer of ashes during the rotation of said shafts, and being of such length as to make substantial wiping contact with the cylindrical surfaces of the members on adjacent shafts during the rotation thereof.

2. A cutting and dumping grate comprising a substantially rectangular frame, shafts rotatable about parallel axes journaled in opposite sides of said frame, fire supporting members spaced apart along each of said shafts, the adjacent ends of the segments on adjacent shafts being substantially in contact with each other when the members are in normal fire supporting position, each member having a finger projecting in the general direction of a plane bisecting the segment and passing through the axis of the supporting shaft, said fingers being shaped at their ends to form scoops for cutting into the superposed layer of ashes during the rotation of said shafts, and being of such length as to make substantial wiping contact twice with the cylindrical surfaces of the members on oppositely adjacent shafts during each complete revolution of said shafts.

IRA C. SMITH. 

